Highly Compressible Wood Sponges with a Spring-like Lamellar Structure as Effective and Reusable Oil Absorbents
Highly Compressible Wood Sponges with a Spring-like Lamellar Structure as Effective and Reusable Oil Absorbents
复制标题
具有类弹簧层状结构的高度可压缩木海绵作为有效且可重复使用的吸油剂
DOI：
10.1021/acsnano.8b05763
复制
发表时间：
2018-10-01
期刊：
影响因子：
17.1
通讯作者：
Wang, Xiaoqing
中科院分区：
文献类型：
--
作者：
Guan, Hao;Cheng, Zhiyong;Wang, Xiaoqing
源自纳米纤维素的气凝胶由于其重量轻、卓越的吸收能力和可持续性而成为用于清理漏油和有机污染物的有吸引力的吸收剂。然而，大多数基于自下而上制造工艺的纳米纤维素气凝胶仍然缺乏足够的机械鲁棒性，因为它们具有随机组装的纤维素纳米纤丝的无序结构，这是它们作为吸油剂的实际应用的障碍。在此，我们报告了一种有效的策略，以创造各向异性纤维素基木材海绵与一个特殊的弹簧状层状结构直接从天然轻木。通过化学处理选择性地去除木质素和半纤维素，打破了天然木材的薄细胞壁，导致在冷冻干燥时具有波浪状堆叠层的层状结构。随后的硅烷化反应允许在骨架表面上生长聚硅氧烷涂层。所得甲硅烷基化的木海绵表现出高的机械压缩性（可逆压缩60%）和弹性恢复性（类似于在40%应变下100次循环后99%的高度保持率）。结果表明，该多孔海绵具有良好的油/水选择性，吸油量可达41 g g（-1）。此外，通过简单的机械挤压可以回收吸附的油，且多孔海绵在多次挤压吸附循环后仍保持较高的吸油量，显示出良好的可回收性。利用多孔海绵的单向液体传输特性，成功设计了一种集油装置，实现了污染物与水的连续分离。这种简单、低成本和可扩展的自上而下的方法对于开发用于油/水分离的有效和可重复使用的油吸收剂具有巨大的潜力。
Aerogels derived from nanocellulose have emerged as attractive absorbents for cleaning up oil spills and organic pollutants due to their lightweight, exceptional absorption capacity, and sustainability. However, the majority of the nanocellulose aerogels based on the bottom-up fabrication process still lack sufficient mechanical robustness because of their disordered architecture with randomly assembled cellulose nanofibrils, which is an obstacle to their practical application as oil absorbents. Herein, we report an effective strategy to create anisotropic cellulose-based wood sponges with a special spring-like lamellar structure directly from natural balsa wood. The selective removal of lignin and hemicelluloses via chemical treatment broke the thin cell walls of natural wood, leading to a lamellar structure with wave-like stacked layers upon freeze-drying. A subsequent silylation reaction allowed the growth of polysiloxane coatings on the skeleton surface. The resulting silylated wood sponge exhibited high mechanical compressibility (reversible compression of 60%) and elastic recovery (similar to 99% height retention after 100 cycles at 40% strain). The wood sponge showed excellent oil/water absorption selectivity with a high oil absorption capacity of 41 g g(-1) Moreover, the absorbed oils can be recovered by simple mechanical squeezing, and the porous sponge maintained a high oil-absorption capacity upon multiple squeezing absorption cycles, displaying excellent recyclability. Taking advantage of the unidirectional liquid transport of the porous sponge, an oil-collecting device was successfully designed to continuously separate contaminants from water. Such an easy, low-cost, and scalable top-down approach holds great potential for developing effective and reusable oil absorbents for oil/water separation.